Wang Qijing, Jiang Sai, Zhang Bowen, Shin Eul-Yong, Noh Yong-Young, Xu Yong, Shi Yi, Li Yun
National Laboratory of Solid-State Microstructures, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China.
Department of Chemical Engineering , Pohang University of Science and Technology , 77 Cheongam-Ro, Nam-Gu , Pohang 37673 , Republic of Korea.
J Phys Chem Lett. 2020 Feb 20;11(4):1466-1472. doi: 10.1021/acs.jpclett.9b03339. Epub 2020 Feb 7.
Despite the increasing understanding of charge transport in organic field-effect transistors (OFETs), charge injection from source/drain electrodes into organic semiconductors remains crucial for improving device performance and lowering power consumption. The analysis of contact resistance is generally carried out without clearly distinguishing the Schottky barrier and access resistance. Here we show that the access resistance through the organic semiconductor bulk can significantly influence the Schottky barrier evaluation and affect the charge-transport exploration. Indeed, access resistance plays a leading role in the contact resistance, whereas the Schottky barrier (expressed as the interface resistance) determines the charge injection at the metal/semiconductor interface. The Schottky barrier evaluation strongly depends on the access resistance and bias voltage. After eliminating the access resistance effect, the intrinsic Schottky barrier appears to be very coincident and weakly dependent on the work function of the contact metal. This work provides clues to understanding the Schottky barrier and charge injection in OFETs to optimize OFETs for high-performance and advanced applications.
尽管人们对有机场效应晶体管（OFET）中的电荷传输有了越来越深入的理解，但从源极/漏极电极向有机半导体的电荷注入对于提高器件性能和降低功耗仍然至关重要。接触电阻的分析通常在没有明确区分肖特基势垒和体电阻的情况下进行。在此我们表明，通过有机半导体本体的体电阻会显著影响肖特基势垒评估，并影响电荷传输研究。实际上，体电阻在接触电阻中起主导作用，而肖特基势垒（表示为界面电阻）决定了金属/半导体界面处的电荷注入。肖特基势垒评估强烈依赖于体电阻和偏置电压。消除体电阻效应后，本征肖特基势垒似乎非常一致，并且对接触金属的功函数依赖性较弱。这项工作为理解OFET中的肖特基势垒和电荷注入提供了线索，以便为高性能和先进应用优化OFET。
